Zhang Yanru, Xiang Yinping, Xu Rui, Huang Jing, Deng Jiaqin, Zhang Xuan, Wu Zijian, Huang Zhongliang, Yang Zhaohui, Xu Jingliang, Xiong Wenlong, Li Hui
Hunan Academy of Forestry and State Key Laboratory of Utilization of Woody Oil Resource, Changsha, 410004, China; School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, China; College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China.
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China.
J Environ Manage. 2023 Jun 1;335:117492. doi: 10.1016/j.jenvman.2023.117492. Epub 2023 Feb 28.
Mobile genetic elements (MGEs) mediated horizontal gene transfer is the primary reason for the propagation of antibiotic resistance genes in environment. The behavior of MGEs under magnetic biochar pressure in sludge anaerobic digestion (AD) is still unknown. This study evaluated the effects of different dosage magnetic biochar on the MGEs in AD reactors. The results showed that the biogas yield was highest (106.68 ± 1.16 mL g VS) with adding optimal dosage of magnetic biochar (25 mg g TS), due to it increased the microorganism's abundance involved in hydrolysis and methanogenesis. While, the total absolute abundance of MGEs in the reactors with magnetic biochar addition increased by 11.58%-77.37% compared with the blank reactor. When the dosage of magnetic biochar was 12.5 mg g TS, the relative abundance of most MGEs was the highest. The enrichment effect on ISCR1 was the most significant, and the enrichment rate reached 158.90-214.16%. Only the intI1 abundance was reduced and the removal rates yield 14.38-40.00%, which was inversely proportional to the dosage of magnetic biochar. Co-occurrence network explored that Proteobacteria (35.64%), Firmicutes (19.80%) and Actinobacteriota (15.84%) were the main potential host of MGEs. Magnetic biochar changed MGEs abundance by affecting the potential MGEs-host community structure and abundance. Redundancy analysis and variation partitioning analysis showed that the combined effect of polysaccharides, protein and sCOD exhibited the greatest contribution (accounted for 34.08%) on MGEs variation. These findings demonstrated that magnetic biochar increases the risk of MGEs proliferation in AD system.
移动遗传元件（MGEs）介导的水平基因转移是抗生素抗性基因在环境中传播的主要原因。在污泥厌氧消化（AD）过程中，MGEs在磁性生物炭压力下的行为仍不清楚。本研究评估了不同剂量磁性生物炭对AD反应器中MGEs的影响。结果表明，添加最佳剂量的磁性生物炭（25 mg g TS）时，沼气产量最高（106.68±1.16 mL g VS），这是因为它增加了参与水解和产甲烷的微生物丰度。然而，与空白反应器相比，添加磁性生物炭的反应器中MGEs的总绝对丰度增加了11.58%-77.37%。当磁性生物炭剂量为12.5 mg g TS时，大多数MGEs的相对丰度最高。对ISCR1的富集效果最为显著，富集率达到158.90-214.16%。只有intI1丰度降低，去除率为14.38-40.00%，这与磁性生物炭的剂量成反比。共现网络探究发现变形菌门（35.64%）、厚壁菌门（19.80%）和放线菌门（15.84%）是MGEs的主要潜在宿主。磁性生物炭通过影响潜在的MGEs-宿主群落结构和丰度来改变MGEs的丰度。冗余分析和变异分配分析表明，多糖、蛋白质和溶解性化学需氧量（sCOD）的综合作用对MGEs变异的贡献最大（占34.08%）。这些发现表明，磁性生物炭增加了AD系统中MGEs增殖的风险。
